diff --git a/server/intellipay/intellipay.js b/server/intellipay/intellipay.js
index a58d45240..169e27fd2 100644
--- a/server/intellipay/intellipay.js
+++ b/server/intellipay/intellipay.js
@@ -8,6 +8,7 @@ const { sendTaskEmail } = require("../email/sendemail");
 const generateEmailTemplate = require("../email/generateTemplate");
 const { SecretsManagerClient, GetSecretValueCommand } = require("@aws-sdk/client-secrets-manager");
 const { InstanceRegion, InstanceEndpoints } = require("../utils/instanceMgr");
+const { isEmpty, isNumber } = require("lodash");
 
 const domain = process.env.NODE_ENV ? "secure" : "test";
 
@@ -57,7 +58,6 @@ const getShopCredentials = async (bodyshop) => {
 const decodeComment = (comment) => {
   try {
     return comment ? JSON.parse(Buffer.from(comment, "base64").toString()) : null;
-    // eslint-disable-next-line no-unused-vars
   } catch (error) {
     return null; // Handle malformed base64 string gracefully
   }
@@ -85,17 +85,17 @@ const lightboxCredentials = async (req, res) => {
 
   const shopCredentials = await getShopCredentials(req.body.bodyshop);
 
-  if (shopCredentials.error) {
+  if (shopCredentials?.error) {
     logger.log("intellipay-credentials-error", "ERROR", req.user?.email, null, {
       message: shopCredentials.error?.message,
       ...logMeta
     });
-    res.json({
+
+    return res.json({
       message: shopCredentials.error?.message,
       type: "intellipay-credentials-error",
       ...logMeta
     });
-    return;
   }
 
   try {
@@ -116,13 +116,14 @@ const lightboxCredentials = async (req, res) => {
       ...logMeta
     });
 
-    res.send(response.data);
+    return res.send(response.data);
   } catch (error) {
     logger.log("intellipay-lightbox-error", "ERROR", req.user?.email, null, {
       message: error?.message,
       ...logMeta
     });
-    res.json({
+
+    return res.json({
       message: error?.message,
       type: "intellipay-lightbox-error",
       ...logMeta
@@ -154,18 +155,17 @@ const paymentRefund = async (req, res) => {
 
   const shopCredentials = await getShopCredentials(req.body.bodyshop);
 
-  if (shopCredentials.error) {
+  if (shopCredentials?.error) {
     logger.log("intellipay-refund-credentials-error", "ERROR", req.user?.email, null, {
       credentialsError: shopCredentials.error,
       ...logResponseMeta
     });
 
-    res.status(400).json({
+    return res.status(400).json({
       credentialsError: shopCredentials.error,
       type: "intellipay-refund-credentials-error",
       ...logResponseMeta
     });
-    return;
   }
 
   try {
@@ -193,13 +193,14 @@ const paymentRefund = async (req, res) => {
       ...logResponseMeta
     });
 
-    res.send(response.data);
+    return res.send(response.data);
   } catch (error) {
     logger.log("intellipay-refund-error", "ERROR", req.user?.email, null, {
       message: error?.message,
       ...logResponseMeta
     });
-    res.status(500).json({
+
+    return res.status(500).json({
       message: error?.message,
       type: "intellipay-refund-error",
       ...logResponseMeta
@@ -233,17 +234,17 @@ const generatePaymentUrl = async (req, res) => {
 
   const shopCredentials = await getShopCredentials(req.body.bodyshop);
 
-  if (shopCredentials.error) {
+  if (shopCredentials?.error) {
     logger.log("intellipay-generate-payment-url-credentials-error", "ERROR", req.user?.email, null, {
       message: shopCredentials.error?.message,
       ...logResponseMeta
     });
-    res.status(400).json({
+
+    return res.status(400).json({
       message: shopCredentials.error?.message,
       type: "intellipay-generate-payment-url-credentials-error",
       ...logResponseMeta
     });
-    return;
   }
 
   try {
@@ -274,13 +275,14 @@ const generatePaymentUrl = async (req, res) => {
       ...logResponseMeta
     });
 
-    res.send(response.data);
+    return res.send(response.data);
   } catch (error) {
     logger.log("intellipay-generate-payment-url-error", "ERROR", req.user?.email, null, {
       message: error?.message,
       ...logResponseMeta
     });
-    res.status(500).json({ message: error?.message, ...logResponseMeta });
+
+    return res.status(500).json({ message: error?.message, ...logResponseMeta });
   }
 };
 
@@ -304,24 +306,24 @@ const checkFee = async (req, res) => {
 
   logger.log("intellipay-checkfee-request-received", "DEBUG", req.user?.email, null, logResponseMeta);
 
-  if (!req.body.amount || req.body.amount <= 0) {
+  if (!isNumber(req.body?.amount) || req.body?.amount <= 0) {
     logger.log("intellipay-checkfee-skip", "DEBUG", req.user?.email, null, {
       message: "Amount is zero or undefined, skipping fee check.",
       ...logResponseMeta
     });
-    res.json({ fee: 0 });
-    return;
+
+    return res.json({ fee: 0 });
   }
 
   const shopCredentials = await getShopCredentials(req.body.bodyshop);
 
-  if (shopCredentials.error) {
+  if (shopCredentials?.error) {
     logger.log("intellipay-checkfee-credentials-error", "ERROR", req.user?.email, null, {
       message: shopCredentials.error?.message,
       ...logResponseMeta
     });
-    res.status(400).json({ error: shopCredentials.error?.message, ...logResponseMeta });
-    return;
+
+    return res.status(400).json({ error: shopCredentials.error?.message, ...logResponseMeta });
   }
 
   try {
@@ -357,34 +359,40 @@ const checkFee = async (req, res) => {
         message: response.data?.error,
         ...logResponseMeta
       });
-      res.status(400).json({
+
+      return res.status(400).json({
         error: response.data?.error,
         type: "intellipay-checkfee-api-error",
         ...logResponseMeta
       });
-    } else if (response.data < 0) {
+    }
+
+    if (response.data < 0) {
       logger.log("intellipay-checkfee-negative-fee", "ERROR", req.user?.email, null, {
         message: "Fee amount returned is negative.",
         ...logResponseMeta
       });
-      res.json({
+
+      return res.json({
         error: "Fee amount negative. Check API credentials & account configuration.",
         ...logResponseMeta,
         type: "intellipay-checkfee-negative-fee"
       });
-    } else {
-      logger.log("intellipay-checkfee-success", "DEBUG", req.user?.email, null, {
-        fee: response.data,
-        ...logResponseMeta
-      });
-      res.json({ fee: response.data, ...logResponseMeta });
     }
+
+    logger.log("intellipay-checkfee-success", "DEBUG", req.user?.email, null, {
+      fee: response.data,
+      ...logResponseMeta
+    });
+
+    return res.json({ fee: response.data, ...logResponseMeta });
   } catch (error) {
     logger.log("intellipay-checkfee-error", "ERROR", req.user?.email, null, {
       message: error?.message,
       ...logResponseMeta
     });
-    res.status(500).json({ error: error?.message, logResponseMeta });
+
+    return res.status(500).json({ error: error?.message, logResponseMeta });
   }
 };
 
@@ -406,19 +414,15 @@ const postBack = async (req, res) => {
   logger.log("intellipay-postback-received", "DEBUG", "api", null, logResponseMeta);
 
   try {
-    if ((!values.invoice || values.invoice === "") && !decodedComment) {
-      //invoice is specified through the pay link. Comment by IO.
+    if (isEmpty(values?.invoice) && !decodedComment) {
       logger.log("intellipay-postback-ignored", "DEBUG", "api", null, {
         message: "No invoice or comment provided",
         ...logResponseMeta
       });
-      res.sendStatus(200);
-      return;
+      return res.sendStatus(200);
     }
 
     if (decodedComment) {
-      //Shifted the order to have this first to retain backwards compatibility for the old style of short link.
-      //This has been triggered by IO and may have multiple jobs.
       const parsedComment = decodedComment;
 
       logger.log("intellipay-postback-parsed-comment", "DEBUG", "api", null, {
@@ -426,18 +430,16 @@ const postBack = async (req, res) => {
         ...logResponseMeta
       });
 
-      //Adding in the user email to the short pay email.
-      //Need to check this to ensure backwards compatibility for clients that don't update.
-
       const partialPayments = Array.isArray(parsedComment) ? parsedComment : parsedComment.payments;
 
-      // Fetch jobs by job IDs
       const jobs = await gqlClient.request(queries.GET_JOBS_BY_PKS, {
         ids: partialPayments.map((p) => p.jobid)
       });
+
       const bodyshop = await gqlClient.request(queries.GET_BODYSHOP_BY_ID, {
         id: jobs.jobs[0].shopid
       });
+
       const ipMapping = bodyshop.bodyshops_by_pk.intellipay_config?.payment_map;
 
       logger.log("intellipay-postback-jobs-fetched", "DEBUG", "api", null, {
@@ -446,7 +448,6 @@ const postBack = async (req, res) => {
         ...logResponseMeta
       });
 
-      // Insert new payments
       const paymentResult = await gqlClient.request(queries.INSERT_NEW_PAYMENT, {
         paymentInput: partialPayments.map((p) => ({
           amount: p.amount,
@@ -476,7 +477,7 @@ const postBack = async (req, res) => {
         ...logResponseMeta
       });
 
-      if (values.origin === "OneLink" && parsedComment.userEmail) {
+      if (values?.origin === "OneLink" && parsedComment?.userEmail) {
         sendTaskEmail({
           to: parsedComment.userEmail,
           subject: `New Payment(s) Received - RO ${jobs.jobs.map((j) => j.ro_number).join(", ")}`,
@@ -500,8 +501,11 @@ const postBack = async (req, res) => {
           });
         });
       }
-      res.sendStatus(200);
-    } else if (values.invoice) {
+
+      return res.sendStatus(200);
+    }
+
+    if (values?.invoice) {
       const job = await gqlClient.request(queries.GET_JOB_BY_PK, {
         id: values.invoice
       });
@@ -551,14 +555,24 @@ const postBack = async (req, res) => {
         responseResults,
         ...logResponseMeta
       });
-      res.sendStatus(200);
+
+      return res.sendStatus(200);
     }
+
+    // Default case: no valid conditions met
+    logger.log("intellipay-postback-invalid", "WARN", "api", null, {
+      message: "No valid invoice or comment provided",
+      ...logResponseMeta
+    });
+
+    return res.status(400).send("Bad Request: No valid invoice or comment provided");
   } catch (error) {
     logger.log("intellipay-postback-error", "ERROR", "api", null, {
       message: error?.message,
       ...logResponseMeta
     });
-    res.status(400).json({ successful: false, error: error.message, ...logResponseMeta });
+
+    return res.status(400).json({ successful: false, error: error.message, ...logResponseMeta });
   }
 };